• Title/Summary/Keyword: wind circulation

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Long-Term Trend of Surface Wind Speed in Korea: Physical and Statistical Homogenizations (한반도 지상 풍속의 장기 추세 추정: 관측 자료의 물리적 및 통계적 보정)

  • Choi, Yeong-Ju;Park, Chang-Hyun;Son, Seok-Woo;Kim, Hye-Jin
    • Atmosphere
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    • v.31 no.5
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    • pp.553-562
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    • 2021
  • The long-term trend of surface wind speed in Korea is estimated by correcting wind measurements at 29 KMA weather stations from 1985 to 2019 with physical and statistical homogenization. The anemometer height changes at each station are first adjusted by applying physical homogenization using the power-law wind profile. The statistical homogenization is then applied to the adjusted data. A standard normal homogeneity test (SNHT) is particularly utilized. Approximately 40% of inhomogeneities detected by the SNHT match with the sea-level-height change of each station, indicating that an SNHT is an effective technique for reconciling data inhomogeneity. The long-term trends are compared with homogenized data. Statistically significant negative trends are observed along the coast, while insignificant trends are dominant inland. The mean trend, averaged over all stations, is -0.03 ± 0.07 m s-1 decade-1. This insignificant trend is due to a trend change across 2001. A decreasing trend of -0.10 m s-1 decade-1 reverses to an increasing trend of 0.03 m s-1 decade-1 from 2001. This trend change is consistent with mid-latitude wind change in the Northern hemisphere, indicating that the long-term trend of surface wind speed in Korea is partly determined by large-scale atmospheric circulation.

광도만에 있어서 물질수송과정의 수치예측

  • 이인철;류청로
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2000.10a
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    • pp.159-164
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    • 2000
  • In order to clarify the seasonal variation of residual current and material transportation process in Hiroshima Bay, JAPAN, the real-time simulation of residual current and particle tracking by using Euler-Lagrange model were carried out. The calculated tidal current and water temperature and salinity showed good agreement with the observed ones. The residual currents showed the southward flow pattern at the upper layer, and the northward flow pattern at the lower layer. The flow structure of residual current in Hiroshima Bay is an estuarine circulation affected by density flow and wind driven current. The residual current plays an improtant role of material transportation in th bay.

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Computation of Wind-Driven Circulation in the East Sea (동해의 풍성류산정)

  • 최병호;이호준
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.5 no.2
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    • pp.121-132
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    • 1993
  • A three-dimensional barotropic model is used to compute meteorologically-induced circulations in the East Sea for monthly, seasonal and annual basis. The computed barotropic responses have shown that in the upper part of the 40$^{\circ}$ North latitude. counterclockwise meso-scale eddies have been formed off Dong Han Man, middle part of the East Sea and sea area between the Siberian coast and Hokkaido throughout the year except summer season. These results are in good agreements with some of earlier schematic circulation diagram.

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Circulation in the Southwestern East Sea (Japan Sea) in July 1993 Determined by an Inverse Method

  • Shin, Chang-Woong;Byun, Sang-Kyung;Kim, Cheol-Soo;Seung, Young-Ho;Lee, Jae-Hak
    • Ocean and Polar Research
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    • v.21 no.2
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    • pp.87-97
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    • 1999
  • To estimate absolute transports by advection in the southwestern East Sea (Japan Sea), an inverse method was applied to CTD data obtained in July 1993. The relative velocities are calculated using the thermal wind equation. The inverse model was formulated to obtain a reference velocity based on the mass conservation in each of four vertical layers within a region enclosed by hydrographic sections and the coastal boundary. The flow patterns in the surface layer are clockwise and anti-clockwise in the regions south and northwest of Ulleung Island, respectively, and a strong northward flow appears in between them. In the second layer, the flow fields are generally weak. The inverse calculation yields the southward flow along the coast, and this suggests that the subsurface low salinity water in the Ulleung Basin is supplied by the southward transport along the east coast of Korea.

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A Numerical Simulation of Residual Current and Material Transportation in Hiroshima Bay, Japan (황도만에서의 잔차류와 물질소송의 수치모형실험)

  • 이인철
    • Journal of Ocean Engineering and Technology
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    • v.15 no.1
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    • pp.45-51
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    • 2001
  • In order to clarify the seasonal variation of the residual current and the material transportation process in Hiroshima Bay, JAPAN, the real-time simulation of residual current and particle tracking by using the Euler-Lagrange model were carried out. The calculated tidal current, water temperature, and salinity showed good agreement with the observed ones. The residual currents showed a southward flow pattern at the upper layer, and a northward flow pattern at the lower layer. The flow structure of the residual current in Hiroshima Bay is an estuarine circulation affected by density flow and wind driven current. The residual current plays an important role of material transportation in the bay.

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A Study on Nonlinear Interaction of Tidal Current and Wind-Induced Current using a Point Model (점모형을 이용한 조류와 취송류의 비선형 상호작용)

  • 이종찬;정경태
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.8 no.1
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    • pp.28-36
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    • 1996
  • The influence of vertical eddy viscosity to the nonlinear interaction of tidal current and wind-induced current is examined using a point model. A zero-equation turbulence model is derived by simplifying the q$^2$-q$^2$1 turbulence model under the assumption that the generation of turbulence kinetic energy is balanced with its dissipation and is further modified to include the depth of frictional influence properly The zero-equation turbulence model is derived and the possibility of resonance in the presence of Coriolis effect is suggested. The amplitudes of tidal currents remain the same regardless of the applied wind stress, but the over-tide component is generated due to the nonlinear interaction of tidal current and wind-induced current. Significant changes in the vertical profile of wind-induced currents can occur according to tide-induced background turbulence. The turbulence model can give rise to misleading results when applied to the wind-driven circulation in the tide-dominated sea such as Yellow Sea unless the tide-induced background turbulence is adequately included in the parameterization of vertical eddy viscosity.

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A literature Study on 竹瀝 (A study for Aquacupunture Experiment of SUCCUS PHYLLOSTACHYOS) (죽력(竹瀝)의 문헌적(文獻的) 고찰(考察)(죽력(竹瀝)의 약침실험(藥鍼實驗)을 위한 문헌적(文獻的) 고찰(考察)))

  • Park, Kyung-Jin;Chae, Woo-Suk
    • Journal of Acupuncture Research
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    • v.18 no.3
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    • pp.184-200
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    • 2001
  • Objective : To research SUCCUS PHYLLOSTACHYOS through 38 kinds texts over generation for acuacupunture experiment of SUCCUS PHYLLOSTACHYOS. Methods : I studied origin, alias, species, tastes, meridian, effect, treatment, component, medical action and contraindication of SUCCUS PHYLLOSTACHYOS through 38 kinds mecical literatures. Results : Medical actions of SUCCUS PHYLLOSTACHYOS are Resolving slippery phlegm, Reducing fever, Nourishing Yin, Expelling wind and Activating blood circulation. Therefore SUCCUS PHYLLOSTACHYOS can be applied to aphonia, wind arthralgia, Diabetes, epilepsy and convulsive seizure in children. Specially for phlegm-retention due to stroke, it must be used with fresh ginger juice.

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Circulation Experiment of the Chinhae Bay using a Three-Dimensional Diagnostic Numercal Model (3차원 진단모델을 이용한 진해만의 수치유동실험)

  • 배삼완
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.33 no.4
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    • pp.360-369
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    • 1997
  • We calculated the residual current forced by buoyancy, wind stress, and tidal stress in the Chinhae Bay using a three-dimensional diagnostic model. The calculated current was also compared with the observation. The flow directs outward from the central area of the Bay in the upper layer, and also forms eddy-shape stucture in the upper and middle layers. The flow of bottom layer shows an opposite pattern compared to those of top and middle layers. The maximum speed was 6.05 em/see (September) and 3.49 cm/sec (November) in the upper layer, and 4.39 cm/sec on both month in the middle layer. The Kinetic energy of November (8.39xlO' W) was larger than that of September (1.24xlO 'W), mainly resulting from larger buoyancy effect in September. In spite of the roughness of the grid size(1 km) and wind date, the calculated flow shows eorrelation(r=0.71) with the observation. We expect that the correlation be increased by increased by adopting the fine grid and the variable coefficients of diffusion and viscosity.

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The literature study on classification of cause and the effect of Acupuncture and Moxibustion treatment for Youk Jeol Poung (역절풍(歷節風)의 병인병기(病因病機)와 침구치료(鍼灸治療)에 관(關)한 문헌적(文獻的) 고찰(考察))

  • Yuh, Bok-Jong;Kim, Gi-Hyun
    • Journal of Haehwa Medicine
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    • v.9 no.1
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    • pp.443-459
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    • 2000
  • The Literatural Study on the classification of cause and the effect of Acupuncture and Moxibustion treatment for Youk Jeol Poung was studied from the viewpoint of therapeutic acupuncture and moxibustion effect. And the results were as follows: 1. Youk Jeol Poung is similar to Tong Bi, Ju Bi, Haeng Bi, Tong Poung. 2. The symptoms of Youk Jeol Poung are pain and weakness, difficulty of flexion, swelling and pain, severe pain etc., at night pain is more severe. 3. The cause, mechanism of Youk Jeol Poung is as follow, due to penetration of the wind, cold, moisture, uder situation of whole body is pain. 4. The main treatment is invigorate vital energy and blood, expel wind - evil, promote diuresis, eliminating phlegm, promote blood circulation, cold, heat - clearing. 5. The basal meridian of acupuncture and moxibustion treatment were the channels of Su Jok Sam Yang.

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Simulation of Indian Summer Monsoon Rainfall and Circulations with Regional Climate Model

  • Singh, G.P.;Oh, Jai-Ho
    • Proceedings of the Korean Quaternary Association Conference
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    • 2004.06a
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    • pp.24-25
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    • 2004
  • It is well known that there is an inverse relationship between the strength of Indian summer monsoon Rainfall (ISMR) and extent of Eurasian snow cover/depth in the preceding season. Tibetan snow cover/depth also affects the Asian monsoon rainy season largely. The positive correlation between Tibetan sensible heat flux and southeast Asian rainfall suggest an inverse relationship between Tibetan snow cover and southeast Asian rainfall. Developments in Regional Climate Models suggest that the effect of Tibetan snow on the ISMR can be well studied by Limited Area Models (LAMs). LAMs are used for regional climate studies and operational weather forecast of several hours to 3 days in future. The Eta model developed by the National Center for Environmental Prediction (NCEP), the Fifth-Generation NCAR/Penn State Mesoscale Model (MM5) and Regional Climate Model (RegCM) have been used for weather prediction as well as for the study of present-day climate and variability over different parts of the world. Regional Climate Model (RegCM3) has been widely . used for various mesoscale studies. However, it has not been tested to study the characteristics of circulation features and associated rainfall over India so far. In the present study, Regional Climate Model (RegCM-3) has been integrated from 1 st April to 30th September for the years 1993-1996 and monthly mean monsoon circulation features and rainfall simulated by the model at 55km resolution have been studied for the Indian summer monsoon season. Characteristics of wind at 850hPa and 200hPa, temperature at 500hPa, surface pressure and rainfall simulated by the model have been examined for two convective schemes such as Kuo and Grell with Arakawa-Schubert as the closure scheme, Model simulated monsoon circulation features have been compared with those of NCEP/NCAR reanalyzed fields and the rainfall with those of India Meteorological Department (IMD) observational rainfall datasets, Comparisons of wind and temperature fields show that Grell scheme is closer to the NCEP/NCAR reanalysis, The influence of Tibetan snowdepth in spring season on the summer monsoon circulation features and subsequent rainfall over India have been examined. For such sensitivity experiment, NIMBUS-7 SMMR snowdepth data have been used as a boundary condition in the RegCM3, Model simulation indicates that ISMR is reduced by 30% when 10cm of snow has been introduced over Tibetan region in the month of previous April. The existence of Tibetan snow in RegCM3 also indicates weak lower level monsoon westerlies and upper level easterlies.

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